It can also occur as the result of a migraine headache, brain-related circulation problems, or medical conditions affecting the retina of the eye or the gel-like substance within the eye called the vitreous.

This article describes possible causes of photopsia, both common and uncommon, and explains exactly what happens when you are seeing stars.

Why Am I Seeing Stars?

When the lining in the back of the eye (retina) senses light, it sends a message to the optic nerve. The optic nerve relays the message to the brain, which then identifies the image.

When you are seeing stars, something other than visible light is stimulating the retina. These false flashes of light are known as phosphenes.

Phosphenes can be triggered by pressing the eyes. They can also happen when neurons in the eye or the brain are stimulated.

Common Cause of Seeing Stars

Pressure on your eyes is the most common cause of seeing stars. The flashes of light you see can be caused by pressure inside the eye or brain.

It usually only lasts for a few seconds. For example, you might see stars when you:

Rub your eyesSneezeCoughStrainVomit

This is not a health concern.

Medical Causes of Seeing Stars

When you see stars for a prolonged period or frequently, there are a number of possible reasons why this may be occurring.

Those discussed in detail here include:

Posterior vitreous detachmentRetinal disordersMigrainesBrain-related causes

You may also see stars due to:

Infection Inflammation Injury Thyroid disease Tumor

Posterior Vitreous Detachment

Posterior vitreous detachment (PVD) is a common condition caused by aging that can cause you to see stars in your vision.

The vitreous is a jelly-like filler inside the eyeball. It keeps the eyeball plump and round. The vitreous is attached to the retina. With normal aging, the vitreous becomes less firm. It can start to shrink and tug on the retina.

If the pulling is strong enough, the vitreous can separate from the retina. When this happens, it can cause a person to see floaters, flashes of light, or stars.

Vision disturbances caused by PVD can look like streaks of light, usually at the side of the field of vision (peripheral vision).

PVD can cause damage to the retina. Even though it can be a normal part of aging, you need to tell your provider if you have any symptoms of PVD so they can monitor you closely.

Retinal Disorders

You may see stars if you have problems with the retina of your eye. You may see stars, flashes, or bands of light if you have a condition like retinal detachment, which occurs when the retina pulls away from its normal position in the eye.

The symptoms of retinal detachment include:

Flashes of light in one or both eyes A dark shadow that seems like a curtain covering part of your field of view An increase in floaters (small dark spots or squiggly lines that float across your field of vision)

Migraines

Seeing stars can also be part of the visual changes (auras) that are a common symptom of migraine headaches. An aura typically lasts about 20 to 30 minutes, then goes away on its own without any treatment.

With some migraines, a visual aura happens without any pain. These are called ocular migraines. The aura can affect one or both eyes.

If you’re having an ocular migraine, you may see:

Rainbow-like colors Flashes of light Stars Zig-zag lines Blind spots

If you see stars and then get a headache, the episode would be diagnosed as a migraine. If you see stars without pain, it would be called a migraine without a headache.

It’s not common but seeing stars can sometimes be a sign of a problem in the areas of the brain that handle vision. For example, it could be that blood is not flowing correctly or because there has been damage to the brain.

Blood vessel disease (cerebrovascular disease) or systemic low blood pressure can cause less blood supply to the brain. When it’s not getting enough blood, the brain may not function well.

Postural hypotension is a sudden drop in blood pressure. The decrease in blood supply can make a person see stars or flashing lights for a few seconds.

Postural hypotension can happen in someone who already has high or low blood pressure when they lie down or stand up too fast.

Summary

Seeing stars is known as photopsia. The individual flashes of light are called phosphenes.

Usually, seeing stars is due to temporary pressure on the eye. This is typically harmless and only lasts for a few seconds.

However, if you see stars often or they last for a long time, see your provider. You may need to have your vision checked and be evaluated for medical causes of seeing stars, such as migraine, blood pressure changes, and others.